In a previous blog post about Service Pack 4, I said the following:

"…from this point forward all you're likely to see are cumulative updates to the SP3 and SP4 branches and, roughly a year from today, mainstream support will only need to maintain the SP4 branch.  You can read more about this in the following blog post from the CSS blog:

Mainstream vs Extended Support and SQL Server 2005 SP4: Can someone explain all of this?"

In that post, I focused on these words in the product lifecycle chart:

"Support ends 12 months after the next service pack…"

And completely ignored the rest of the sentence, which reads:

"…or at the end of the product's support lifecycle, whichever comes first."

Sure enough, the end of mainstream support for the base product is April 12, 2011, and since this is earlier than December of 2011, this is what we get.  What does it mean?  Well, you can expect probably one more cumulative update for SQL Server 2005 SP4, and possibly one more cumulative update for SQL Server 2005 SP3.  After that, it will be out of support unless you have an explicit support contract set up – any fixes that aren't security-related will require a service agreement.  Extended support for 2005 SP3 will end in December of 2011, and extended support for SP4 will last until April of 2016.

I'm pointing this out because it was made clear in a recent CSS blog post, but the post was about SQL Server 7.0, so you may have missed it.  And the product lifecycle table for SQL Server has not been updated for SQL Server 2005 SP4.

Big thanks to Chris Wood who pointed this out to me this morning – I had missed it too.